This page helps with Property Tax tasks in St. Clair County, Illinois, including looking up real estate or mobile home tax information, checking payment options, and finding the Treasurer’s Office contact details.
Use the St. Clair County Property Tax Inquiry for parcel, owner, address, sales, advanced, or mobile home searches. For payments and payment questions, the St. Clair County Treasurer’s Office is the main public contact.
St. Clair County Property Tax Inquiry
The St. Clair County Property Tax Inquiry is the main online lookup tool for real estate and mobile home tax information. The system supports several search paths, so choose the one that matches the information you have.
- Parcel search: 11-digit parcel number or owner name.
- Address search: house number, street name, and city.
- Sales search: sale price range and sale date range.
- Advanced search: property classes, townships, tax districts, and tax year criteria.
- Mobile home search: mobile home number, owner name, or site address.
The inquiry system notes that data was updated on 2026-06-18 at 17:15:00. Review the county disclaimer before relying on results for payment or tax planning.
Pay St. Clair County property taxes online
Use the St. Clair County Treasurer/Collector online payment portal to find a bill by parcel or mobile home number, name, or address. The portal recommends excluding punctuation when searching.
- Select a payment type.
- Search for the bill by parcel or mobile home number, name, or address.
- Add one or more bills to the cart.
- Review the cart before checkout.
- Create an account or check out as a guest.
- Enter payment details to attempt the payment.
Corrected bills with new due dates cannot be honored through the online payment or Autoagent system. Pay those at the Treasurer’s Office to avoid penalty.
Payment methods and fees
St. Clair County real estate taxes may be paid by mail, at the Treasurer’s Office, at listed financial institutions, or online. Local financial institutions can accept real estate tax payments only through the second due date.
| Payment option | Key details |
|---|---|
| Treasurer’s Office | Accepts in-person payments by cash, check, money order, or cashier’s check. |
| Online payment portal | Accepts Visa, MasterCard, Discover, American Express, and e-check payments. |
| Local financial institutions | Accept real estate tax payments through the second due date only. |
| Available for real estate tax payments. |
Online payments include processor fees. Fees are not collected by the County Treasurer and are not refundable in all circumstances.
| Payment type | Convenience fee |
|---|---|
| Credit card | 2.5% or $2.00 minimum. |
| Debit card | 2.5% or $2.00 minimum. |
| Electronic check | $1.50 for transactions up to $50,000. |
Online tax payments may take three to five business days to process.
2025 real estate tax collection dates
These dates apply to 2025 real estate taxes payable in 2026. Office hours for collection dates are 8:30 AM to 4:30 PM, and all dates are tentative until further notice.
| Event | Date |
|---|---|
| Tax bills mailed | May 26, 2026 |
| First due date | July 1, 2026 |
| Second due date | September 1, 2026 |
| Last day to avoid publication | September 18, 2026 |
| Certified notices mailed | September 25, 2026 |
| Newspaper publications | September 28 - October 2, 2026 |
| Tax buyer registration deadline | October 16, 2026 |
| Last day to pay | October 30, 2026 |
| Tax sale | November 2, 2026 |
Electronic payments stop at 3 PM on the listed cutoff dates, and postmarks are not accepted for those deadlines.
Partial payments and late penalties
Partial payments can be accepted only by the Treasurer’s Office. Collector banks do not accept partial payments.
Partial payments work as an installment payment plan. Illinois imposes a 1.5% monthly penalty on the unpaid balance for late payments. The first installment is late after the published first installment date, and the second installment is late after the published second installment date.
Balances must be paid in full by September 18, 2026 to avoid newspaper publication. Balances must be paid by 4:30 p.m. on October 30, 2026 in the Treasurer’s Office to prevent taxes from going to tax sale.
Monthly payment plan and reminders
The St. Clair County Treasurer’s Office offers a monthly payment plan through EquaPay for homeowners and businesses whose property taxes are not escrowed through a mortgage. The plan can split an annual property tax bill into monthly payments.
- Search the tax bill by name, address, or property ID.
- Create an account and choose a draft date.
- Select ACH or credit card as the payment method.
- Enroll so EquaPay can calculate monthly payments based on the time left before the due date.
The Treasurer’s Office also provides an e-reminder option for tax bill due date reminders.
How St. Clair County property taxes are calculated
Property tax bills are based on taxing districts listed on the tax bill. The county assessor sets an assessment for land and buildings using sale figures from the prior three years.
The assessment determines the Local Value. Approved exemptions are subtracted from the Local Value to calculate the Taxable Value. The Taxable Value is then multiplied by the Tax Rate to determine the amount due.
The Tax Rate is the combined rate for the taxing bodies listed on the bill. For the 2025 tax year payable in 2026, the first half is due on or before July 1, 2026, and the second half is due on or before September 1, 2026.
St. Clair County Treasurer contact
Contact the Treasurer’s Office for property tax payment questions, partial payments, corrected bill payment issues, and tax bill assistance.
-
St. Clair County Treasurer’s Office, #10 Public Square, Belleville, IL 62220
Phone: (618) 825-2707
Fax: (618) 825-2274
Email: [email protected]
Business hours: M-F 8:30am - 4:30pm -
St. Clair County Assessor
Phone: (618) 825-2704
Common questions
Where can I look up St. Clair County property tax information?
Use the Property Tax Inquiry to search by parcel number, owner name, address, sales criteria, advanced criteria, or mobile home information.
Can I pay St. Clair County property taxes online?
Yes. Use the online payment portal to find a bill, add it to the cart, and check out. An account is not required for checkout.
What fees apply to online property tax payments?
Credit and debit card payments have a 2.5% fee or a $2.00 minimum. Electronic check payments have a $1.50 fee for transactions up to $50,000.
When are 2025 St. Clair County real estate taxes due?
For 2025 real estate taxes payable in 2026, the first installment is due July 1, 2026, and the second installment is due September 1, 2026.
Who accepts partial property tax payments?
Only the St. Clair County Treasurer’s Office accepts partial payments. Collector banks do not accept partial payments.
Who should I call with payment questions?
Call the St. Clair County Treasurer’s Office at (618) 825-2707 for property tax payment questions.